Zoe is right, assist feeding is starting the snake off and letting them do the job, force feeding is forcing them to feed, like a pinkie pump.
This is how i assist feed small hatchlings(childrens, carpets etc) it's not hard.
I hold the snake just behind the head, not the head as you want it to open it's mouth, then take a small pinkie( the smaller the better) and push it's nose against the front of the snakes mouth, where the tongue comes out.
Slowly roll and push the pinkies head against the snakes mouth, be gentle, normally the snake will open it's mouth very quickly if you get the right spot and then it's just a matter of pushing the pinkie down until it looks like the head is in the snakes throat, just behind the head.
Then slowly let go and freeze, if you move they will spit it out, alot of the time they will move backwards trying to spit the pinkie out but if it's down far enough they will stop moving and swollow it.
Do this with the snake close to the cage floor so when you let it go it's sitting on the cage floor.
Some snakes will just keep spitting pinkies out if this happens try a 2-3cm peice of adult mouse tail, do it the same way as a pinkie but be sure the hairs on the mouse tail are facing away from the snake, this stops them spitting it out.
Normally it only takes one or two feeds to get them going, the most i've had was 8.
Don't try this day after day, leave it a week and then try again, you can try it several times in one session.
I've probably just confused you but i tried, it's hard to explain.
